This is the title of my first blog post on MySQL Performance
Blog. It deals with a customer case where the customer was facing
a peculiar problem where the rows column in the EXPLAIN output of
the query was totally off. The actual number of rows was 18 times
more than the number of rows reported by MySQL in the output of
EXPLAIN. Now this can be a real pain as MySQL uses “the number of
rows” estimation to pick and choose indexes and it could really
be picking up a wrong index simply because of the wrong estimate.
You...

The more I go through others SQL, there are some common mistakes
that I see developers making over and over again, so I thought
why not start a series of tips that can help developers optimize
their queries and avoid common pitfalls. So this post is a part
of that series of tips, and this is the first tip "Avoid using a
wild card character at the start of a LIKE pattern".

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